Hello all i have a 2002 saturn l200. About a month ago the fuel gauge went to full tank for less then half and the idiot bell was going off. I pulled the positive cable and reset it and all was well. It started to do it again and the reset trick isn't working this time. i have a feeling its the fuel level sending unit but im not sure. And if it is i heard that it is in the gas tank. Any ideas on what it might be? any help would be much appreciated.

I'm betting on a defective sending unit, but I'll stand to the side, and let some of the "bulging brains" in here wade in on this ...

Well where do you think you might find the fuel sending unit, at the corner bakery? Fuel pump assembly is in the fuel tank, and the tank must be dropped to replace it. So having very little fuel in the tank will make matters easier.

After driving it around it fixed the problem. Until it sat for 2 days. Now my fiance tells me that its doing it again but now the security light is blinking. Would a battery that is going low cause this kind of problem?

low battery voltage/current can lead to all sorts of unintended behavior-- but only 1 gauge on the cluster acting up (assuming it is gauge related which we don't know is at all the case) is in my mind low percentage.

Would expect other issues more serious than this if low battery voltage/current was an issue

So the fiance drove the car around for about 30 mins with the bell dinging away, the security light was blinking and the fuel guage was at full tank in error again. When she started the car for the trip home the guage was reading correctly and the bell was silent and the security light wasnt blinking. I get home a few hours later and check the open cell voltage and its at 14.45 volts and started the car and all was well. She didnt drive the car today and the open cell voltage was 12.2. I started the car and the problems returns. Went to auto zone and got a new battery. Come to find out the old battery had 200 cold cranking amps less then recomended. Put the proper battery in and all is well. Hopefully that was the problem.

Let us know if that takes care of it. I'm curious as to what it is. I may be old, but I still like to learn things!

Hello all I apologize for the late update. After I changed the battery the car was once again fine for about a month then it started acting up again. It is still intermittent. The fuel gauge reads full the security light either blinks or stays on solid and the bell dings. It started to only record 4 or so miles on the trip mileage then reset. I reset power and that fixed that problem. One thing I noticed and it’s probably been doing it all along is when everything thing seems normal the fuel gauge will move around randomly. Not all the time but sporadically. Could a faulty fuel sending unit be the cause of all these problems?

Just out of curiosity, what is the open cell voltage on your brand new battery?

It was 13.5 if i remember correctly.

OK so i took the car in and had the fuel level sender and pump replaced. The car still goes to full tank of gas and the security light stays on solid and the bell goes off. Also when the key is in the ON position the car doesn't ding it only does it when the car is running. I'm at a loss.

Hello all sorry for the late response. I have taken the car to a friend of a friends shop and I explaned the symptoms. The tech tested the gague cluster and it all tested good. The tech said that he is 99.9 percent sure its the BCM. So once the tech can determin if he can program the BCM i will get that changed. Ill keep you guys posted.